You're going to have to explain more. What connections are you using? HDMI? or? What did you do in the PS3 and your Blu-Ray disc player to send hd to the avr (the PS3 and BDP units are sources, so they don't literally accept anything). What did you do to setup the avr to handle the input? Are you getting video okay?
HDMI from PS3 and BluRay to AVR then to hdmi from avr to tv? Is this all new gear to you or something changed recently? On the PS3 you used Sound Settings>Audio Output Settings>HDMI>Automatic? Did you set Video Settings for BD/DVD audio? The PS3 is slim or fat version? Which BluRay player? Why pcm on the BluRay?
You might search for hdmi issues for that Onkyo model, some Onkyos have had issues; don't know if that would be an audio only issue, though (think it was more complete hdmi board failure).
You made sure that for each input on the Onkyo that they're set to HDMI rather than optical etc? Running out of ideas, hopefully someone else will have some (you might also find the official 626 thread and post there too). Do you get audio from any source, try the digital coax/optical inputs or composite inputs? Check the 626 manual troubleshooting section?